The setting up of round timber or other workpieces to be split, up by a dividing means, particularly in the longitudinal direction, with respect to the dividing tool (band saw, frame saw, or the like), which is important for optimum guidance of the dividing plane (cutting plane), especially in sawmill operation, is executed, if auxiliary means are at all provided for this purpose, with the aid of light beams (shadows) or with the help of a laser beam.
These conventional measures have the drawback that the work place must always be in darkness since light beams (shadows) or laser beams can hardly be seen, or cannot be seen at all, in sunlight and/or daylight. Recognition is practically not possible at all if wood in its bark is to be split up. When using a laser beam for setting up purposes, the cutting plane can be indicated only at a relatively short range (4-6 m).
Another disadvantage in the conventional measures resides in that the operator must constantly watch the wood or other workpiece to be divided, requiring continuous head movements which are very tiring.
A further drawback of the known measures resides in that adjustment of the workpiece to be split with the aid of a laser beam requires a very expensive arrangement.
Moreover, the operator must be in the immediate vicinity of the workpiece (wood) to be divided in order to be able at all to perform setting up (adjustment) of the workpiece to be divided.
DE-A-2,740,985 discloses a device for the measurement, setting, and feeding of tree trunks to a frame saw. In this conventional device, three television cameras are mounted so that they cover the tree trunk, to be fed to the frame saw, from above and transmit data corresponding to its outer contour to a computer; the latter controls a turning means for the tree trunk resting on the trunk carriages, which is linked to the carriages, in such a way that the log is maximally favorably aligned with regard to the cutting plane.
A similar apparatus is set forth in U.S. Pat. No. A-4,458,567 wherein two cameras are arranged laterally above a log; the log is to be oriented in such a way that the images of contours detected by the cameras are essentially mirror images of one another.
Neither the cameras provided in the device according to DE-A-2,740,985 nor those in the device in accordance with U.S. Pat. No. A-4,458,567 cover the end face of the workpiece to be divided, but rather detect merely its longitudinal sides so that it is merely possible with the known devices to turn logs to be split up into the position favorable for performing a dividing cut. The conventional devices, though, involve comparatively complicated installations utilizing computers which control the necessary turning movements of the log.